|Publication number||US4956492 A|
|Application number||US 06/944,545|
|Publication date||Sep 11, 1990|
|Filing date||Dec 19, 1986|
|Priority date||Mar 14, 1984|
|Publication number||06944545, 944545, US 4956492 A, US 4956492A, US-A-4956492, US4956492 A, US4956492A|
|Inventors||Abraham R. DeKraker, David J. Martella|
|Original Assignee||Exxon Research And Engineering Co.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (4), Classifications (12), Legal Events (3)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This is a division, of application Ser. No. 589,536, filed 3/14/84, now U.S. Pat. No. 4,670,130.
1. Field Of The Invention
The invention relates to copolymers of dialkyl fumarate and vinyl acetate, wherein a major weight proportion of said alkyl groups are C20 to C24 alkyl groups, which copolymers are useful in dewaxing oil, particularly in propane dewaxing processes.
2. Description Of The Prior Art
U.S. Pat. No. 3,729,296 discloses copolymers of long chain dialkyl fumarate and vinyl acetate, as a wax crystal modifier, including use as a dewaxing aid.
U.S. Pat. No. 4,377,467 describes the use of different polymers as dewaxing aids including the use of mixtures of different dewaxing aid polymers.
The present invention represents a further improvement over U.S. Pat. No. 3,729,296 by the finding that forming the copolymer within certain specific viscosity ranges improves the performance of the polymer as a filtration aid in propane dewaxing.
The dialkyl fumarate will have 50 to 100 wt. %, preferably 70 to 100 wt. % of its alkyl groups in the C20 to C24 range. The remaining alkyl groups may be either above C24 or below C20, such as groups derived from tallow alcohols, or even methyl or ethyl alcohols, e.g., see U.S. Pat. No. 3,765,849. Behenyl alcohol is especially preferred for forming the fumarate. The copolymer is formed under nitrogen by a free radical reaction by heating in a solvent the monomers together in about equi-molar proportions, with a free radical initiator, such as a peroxide. However, the overall conditions of time, temperature, peroxide, amounts of solvent, peroxide, etc. are chosen to form polymers having a Specific Viscosity of about 2.5 to 8 or higher, e.g. about 2.7 to 6, preferably 2.7 to 4.5, when measured as a 2 wt. % solution of the copolymer in mixed xylenes at 40° C.
Any waxy petroleum oil stock or distillate fraction thereof may be dewaxed employing the dewaxing aid of this invention, although heavy feedstocks are preferred. Illustrative but non-limiting examples of such stocks are (a) distillate fractions that have a boiling range within he broad range of from about 250° to 700° C., with preferred stocks including lubricating oil and specialty oil fractions boiling within the range of from between about 300° and 650° C. and (b) bright stocks and deasphalted resids having an initial boiling point above about 425° C. Additionally, any of these feeds may be hydrocracked prior to distilling or deasphalting. These may come from any source such as paraffinic crudes obtained from Aramco, Kuwait, the Panhandle, North Louisiana, etc., naphthenic crudes, such as Tia Juana, Coastal crudes, etc., as well as the relatively heavy feedstocks such as bright stocks having a boiling range of 565+° C. and synthetic feedstocks derived from Athabasca tar sands, Cold Lake crude, coal, etc.
A solution of dewaxing aid dissolved in an appropriate solvent such as a light heating oil or a light mineral oil fraction is mixed into the wax-containing oil and the mixture heated to a temperature higher than the cloud point of the oil (about 50° to 120° C.). This mixture is introduced, along with the dewaxing solvent, into a chilling zone and chilled to a temperature necessary to yield the desired pour point for the resulting dewaxed oil. The chilling produces a slurry comprising dewaxed oil and solvent along with solid particles of wax which contain the dewaxing aid. This slurry is then sent to a wax filter to separate the dewaxed oil and solvent from the wax particles.
The ratio of solvent to waxy oil would generally range from about 0.5 to 10 and preferably from 0.5 to 3.0 volumes of solvent per volume of oil. The optimum amount of dewaxing solvent employed is of course determined by the wax content of the oil, viscosity, pretreatment and dewaxing conditions.
The dewaxing aid is added to the waxy oil feed in an amount ranging from about 0.01 to 0.50 wt. % and preferably from about 0.02 to 0.2 wt. % of the oil.
Other dewaxing aids, each in similar amounts i.e. 0.01 to 0.50 wt. %, preferably 0.02 to 0.2 wt. %, based on the weight of oil may also be added. Acryloid 150 which is a methacrylic acid ester polymer is frequently used as such a co-dewaxing aid, e.g. see U.S. Pat. No. 4,377,467, and has been found particularly useful with the fumarate-vinyl acetate copolymers of the invention.
The invention will be further understood by reference to the following examples.
A copolymer of behenyl fumarate and vinyl acetate having a Specific Viscosity of 3.0 when measured at a concentration of 2 wt. % polymer in 98 wt. % xylene at 40° C. was prepared as follows:
Behenyl fumarate (456 g), vinyl acetate (148 g), and cyclohexane (372 g) are charged to a resin kettle and sparged with nitrogen. The mixture is heated under a nitrogen blanket to 75° C. with stirring until it is completely dissolved. Benzoyl peroxide (0.43 g) in ethyl acetate (˜10 g) is sparged with nitrogen and added to the mixture. After six hours the behenyl fumarate is completely consumed and the reaction is quenched with 2,6-di-tert-butyl cresol (0.40 g). The yield of polymer based on behenyl fumarate is 98%.
The above polymer, along with polymers of Specific Viscosity of 0.3, 2.2, and 4.9 were tested in the propane dewaxing of a 600 Neutral Oil (600 SUS viscosity at 100° C.) under conditions simulating commercial plant operation. The oil was diluted with 1.4 to 1.6 volumes of propane per volume of oil. The fumarate-vinyl acetate copolymer was added at a treat rate of 0.03 wt. % active ingredient (a.i.) of copolymer, based on the weight of the oil. Acryloid 150 was also added as a co-dewaxing aid at a treat level of 0.040% a.i., based on the weight of oil. The test results are summarized in the following Table 1.
TABLE 1______________________________________EFFECT OF BEHENYL FUMARATE-VINYLACETATE MOLECULAR WEIGHT ONDEWAXING PERFORMANCESpecific Feed Filter Dewaxed OilViscosity Rate (m3 /m2 /d) Yield (%)______________________________________0.3 9 592.2 9 643.0 39 734.9 32 71______________________________________
As seen by the above data, the higher Specific Viscosities gave a much more rapid filtration rate (and a higher yield of dewaxed oil. Filter rates of 39 cubic meters per square meter of filter surface per day (m3 /m2 /d) were obtained at 3.0 Specific Viscosity which appeared about optimum with this oil.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US3729296 *||Oct 14, 1966||Apr 24, 1973||Exxon Research Engineering Co||Polymeric wax crystal modifiers for high wax content petroleum oils|
|US3765849 *||Jul 7, 1971||Oct 16, 1973||Exxon Research Engineering Co||Flow improvers for hydrocarbon oils and method of preparing same|
|US4377647 *||Nov 16, 1981||Mar 22, 1983||Shell Oil Company||Polymer blend composition|
|US4470421 *||May 3, 1982||Sep 11, 1984||Philip Morris, Incorporated||Smoking compositions|
|US4515974 *||Jun 25, 1982||May 7, 1985||Bayer Aktiengesellschaft||Process for the preparation of fumaric acid monoesters|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US5098550 *||Oct 3, 1990||Mar 24, 1992||Rohm Gmbh||Method for dewaxing waxy petroleum products|
|US5840285 *||Nov 19, 1993||Nov 24, 1998||Bernel Chemical Co., Inc||Dermatological compositions using a series of unusually safe esters as cosmetic emollients with unique and ideal physical properties|
|US6475963||May 1, 2001||Nov 5, 2002||Infineum International Ltd.||Carboxylate-vinyl ester copolymer blend compositions for lubricating oil flow improvement|
|US6583247||Mar 16, 1999||Jun 24, 2003||Infineum International Ltd.||Process for producing free radical polymerized copolymers|
|U.S. Classification||560/190, 208/33, 526/325|
|International Classification||C08F222/10, C08F218/08, C10G73/04|
|Cooperative Classification||C10G73/04, C08F222/10, C08F218/08|
|European Classification||C08F218/08, C10G73/04, C08F222/10|
|Apr 19, 1994||REMI||Maintenance fee reminder mailed|
|Sep 11, 1994||LAPS||Lapse for failure to pay maintenance fees|
|Nov 22, 1994||FP||Expired due to failure to pay maintenance fee|
Effective date: 19940914